Effects of curdlan on the quality of frozen steamed bread: quality changes, water state and starch crystallinity

Summary The purpose of the study was to explore the effects of curdlan on the textural and sensory qualities of frozen steamed bread (FSB), as well as water state and starch properties during freezing. The results showed that incorporation of curdlan improved the springiness and resilience, while it reduced the hardness and chewiness of FSB. The quality deterioration of FSB was largely caused by the growth and recrystalisation of ice crystals. However, incorporation of curdlan mitigated this adverse impact by regulating water state. Specifically, it increased water content, inhibited water migration, and significantly decreased freezable water content. Additionally, curdlan also decreased starch relative crystallinity, which hindered its retrogradation and thus maintained the overall quality of FSB. Notably, inclusion of 0.5% curdlan exhibited optimal effectiveness in improving quality as evidenced by the highest sensory score obtained. This research intended to investigate how curdlan affected frozen steamed bread by analysing variations in textural properties, moisture state, and starch crystallinity during frozen storage. The results showed that curdlan could decrease the hardness and chewiness of frozen steamed bread, increase the specific volume and total moisture content, inhibit water transformation and migration, prevent starch retrogradation, and improve the sensory quality.